Linear motor, and stage apparatus and exposure apparatus using the same
First Claim
Patent Images
1. A linear motor comprising:
- a coil; and
a yoke having a plurality of permanent magnets, each of said magnets being of the same rectangular parallelopiped shape and being arranged along a relative moving direction between said coil and said yoke while rotating polarity directions thereof 90°
each in turn to generate a nearly sinusoidal magnetic field.
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Abstract
In order to provide a good linear motor device which can enjoy low cost and high driving power but has small thrust ripples, in a linear motor in which permanent magnets move relative to a coil, a plurality of permanent magnets are arranged along the moving direction while rotating their polarity directions 90° each in turn to generate a sine magnetic field. Each permanent magnet has a simple rectangular parallelopiped shape, and two or more coils of a polyphase coil are simultaneously energized.
26 Citations
17 Claims
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1. A linear motor comprising:
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a coil; and a yoke having a plurality of permanent magnets, each of said magnets being of the same rectangular parallelopiped shape and being arranged along a relative moving direction between said coil and said yoke while rotating polarity directions thereof 90°
each in turn to generate a nearly sinusoidal magnetic field. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A linear motor comprising:
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a coil; and a yoke having a plurality of permanent magnets which are arranged along a relative moving direction between said coil and said yoke while rotating polarity directions thereof 90°
each in turn to generate a nearly ideal sinusoidal magnetic field,wherein a permanent magnet having a volume smaller than said plurality of permanent magnets is arranged at a terminal end portion of said plurality of permanent magnets. - View Dependent Claims (12, 13)
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14. A linear motor comprising:
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a coil unit; and a plurality of permanent magnets, each of said magnets being of the same rectangular parallelopiped shape and being arranged along a direction of a driving force generated by said linear motor while rotating polarity directions thereof 90°
each in turn to generate a nearly sinusoidal magnetic field. - View Dependent Claims (16)
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15. A linear motor comprising:
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a coil unit; and a plurality of permanent magnets which are arranged along a direction of a driving force generated by said linear motor while rotating polarity directions thereof 90°
each in turn to generate a nearly ideal sinusoidal magnetic field,wherein a permanent magnet having a volume smaller than said plurality of permanent magnets is arranged at a terminal end portion of said plurality of permanent magnets. - View Dependent Claims (17)
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Specification
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Current AssigneeCanon Kabushiki Kaisha (Canon Inc.)
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Original AssigneeCanon Kabushiki Kaisha (Canon Inc.)
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InventorsKamata, Shigeto
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Primary Examiner(s)Ramirez, Nestor
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Assistant Examiner(s)Jones, Judson H.
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Application NumberUS08/845,884Time in Patent Office1,023 DaysField of Search310/12, 310/13, 310/14, 318/135US Class Current310/12.21CPC Class CodesG03F 7/70758 Drive means, e.g. actuators...H02K 41/03 Synchronous motors; Motors ...
